Barium di(dihydro abietyl) dithiophosphate and the method of making the same



Patented Mar. 14, 1944 UNITED STATES PATENT ,orrica BARIUM nimrnrir rnmrni nrrnlo- V I I PHOSPHATE AND THE METHOD OF ING THE SALE MAK- Elmer W.'Cook,-New York, N. Y., and D. Thomas, Jr., Stamford, Conn assignors to American Cyanamid Company. New York, N. Y1,

a corporation of Maine No Drawing. Application April'i'i, 1942,

I 1 Serial No. 439,399

2 Claims.

This invention relates to new chemical compounds and theirpreparation, more particularly to dithiophosphoric acid esters of abietyl alcohols;

salts of such acid esters and methods of preparing the same.

As is generally known the naturally occur-ring wood and gum rosins consistprincipally of abietic acid and smaller amounts of isomeric acids suchas d-pimeric. sapinic, etc. These acids are tricyclic hydroarornatic acids, possessing an alkylated phenanthrene nucleus, of the general formula C19H29COOH. These acids and their esters-may be reduced by hydrogenation processes in known manner to yield a series of abietyl alcohols and isomers thereof, the principal ones of which are abietyl alcohol, dihydro-abietyl al cohol, tetrahydro-abietyl alcohol and dehydroabietyl alcohol, the latter possessing a dialicyclicmonoaryl cyclic structure.

We have now discovered, and this discovery constitutes an essential feature of the present invention, that these alcohols may be reacted with P285 to yield dithiophosphoric acid esters of abietyl alcohols and that the salts of these acid esters may be prepared in the manner to be hereinafter described. The present invention is directed therefore principally to'the preparation of such acid esters and their salts as new chemical compounds.

The compounds of the present invention have an unexpectedly high solubility in hydrocarbon lubricating oils and when added thereto in small amounts are found to have the unusual characteristic of showing anti-oxidantproperties in preventing decomposition of the oil when employed at high temperatures under severe lubricatin conditions. These new compounds act as corrosion inhibitors preventing corrosion'of certainz alloy bearings'and other metal parts in internal combustion engines. They have also'been found useful as detergents and dispersing agents in lubricating oils in which they prevent formation of sludge "and prevent formation on the pistons and other parts of the engine of lacquer-like deposits which cause sticking of the piston rin s and sometimes even the piston itself. Being waterinsoluble and polar in character they are also valuable in the'preparation of slushing oils. Because of their sulfur and phosphorus content they may be advantageously added to hypoid gear lubricants and other high pressure lubricants. Compounds of the present invention are also useful in the flotation of ores and some of their salts, particularly their lead and mercury salts, may be employed in insecticides and fungicides. Be-

ing thick, viscous liquids of goal heat stability they also are of value as plasticizers, particularly for synthetic rubber.

Our new compounds may be prepared by heat:

' ing a'rosin-derived alcohol of the group c0nsist- I ing of abietyl alcohol, dihydro-abietyl alcohol.

" tetrahydro-abietyl alcohol and dehydro-abietyl alcohol with phosphorus pentasulfide (P285) at temperatures of the order of -110-C.-; the reaction of 1 mole of P285 with 4 mole of the abietyl alcohol resulting in the formation'of 2 moles of a dithiophosphoric acid ester of the corresponding abietyl alcohol with the elimination of 1 mole of Has. The reaction may be brought about by merely mixing P285, preferably in a finely ground form, with the desired abietyl alcohol with heating and stirring until the evolution of -H2S has practically ceased. Should excessive foaming occur due to the evolution of Has the addition of a small amount of toluene to the reaction mixture will reduce the foaming to a point at which it is no longer troublesome. The crude di(abietyl) dithiophosphoric acid ester is obtained in the form of a viscous liquid whichv may be decanted from the unreacted P285. Thedesired salt-of the di- (abietyl). dithiophosphoric acid ester may then be prepared by simple neutralization of the compound with salt-forming bases orfby double decomposition with its sodium salt.

As pointed out above the abietyl alcohols which may beemployed by us in the preparation of our new compounds are knownproducts derived by the reduction, usually catalytic hydrogenation, of abietic acid or a primary, secondary or tertiary ester of abieticacid or hydroabitic acid. The

product usually contains mixtures of the various v abietyl alcohols depending upon. the particular conditions employed in the hydrogenation. The

' salt-forming radicals including those such as nickel, aluminum, lead, mercury, cadmium, tin, zinc, magnesium, sodium-potassium, ammonium,

fication well.

The preparation of our new compounds will now be described in greater detail by means oi the following example to which, however, our invention is not limited since it is given merely for purposes of illustration. Obviously, modifications thereof may be made. without departing from the scope of our invention as set forth in the appended claims.

1810 parts by weight of dihydro-abietyl alcohol and 382 parts by weight of finely ground P285 were heated with stirring at 100-105 C. for 8 hours. At the end of this time most the P285 had reacted and the evolution of H28 had practically ceased. The crude di(dihydro-abietyl) dithiophosphoric acid thus obtained was decanted from unreacted P285. The product was a viscous liquid with a light blackish-brown color.

The barium salt of di(dihydro-abietyl) dithiophosphoric' acid was prepared as follows: 2100 parts by weight of di(dihydro-abletyl) dithiobarium sulfide in this preparation is advantageous in that the formation of water during the neutralization is avoided, H18 being formed instead and is evolved from the reaction mixture during the neutralization. The other abietyl alcohols may be reacted with P285 in the same way as described above using similar proportions of materials. For this reason description of the preparation oi-these products is not thought necessary.

When these esters are to be added to lubricating oils as detergents, sludge dispersants and cor-' rosion inhibitors it is convenient to add a suitable hydrocarbon lubricating oil such as 10-W grade to the preparation before all of the solvent has been evaporated. In this way it is possible to obtain a concentration of the abietyl ester in lubricating oils of as high as which composition may be sold, shipped and stored as such for convenient handling and blending purposes.

These compounds have also been found to exert solubilizing effects on other less oil-soluble alkyl esters of dithiophosphoric acids such as barium diamyl dithiophosphate and the two types of esters may be advantageously blended beiore being incorporated in a lubricating oil.

What we claim is: 1. Barium di(dihydro-abietyl) dithiophosphate. 2. A mehod' of preparing barium salts of di(dihydro-abietyl) dithiophosphate which comprises heating dihydro-abietyl alcohol with P385 until the evolution of H28 has substantially ceased and neutralizing the resulting product with barium oxide.

' ELMER W. COOK.

WILLIAM D. THOMAS, JR. 

